quietone
--- a/core/modules/system/system.install
+++ b/core/modules/system/system.install
    }
    $requirements['update status']['title'] = t('Update notifications');

+    if (Settings::get('development_mode', FALSE)) {
--- a/core/assets/scaffold/files/default.services.yml
+++ b/core/assets/scaffold/files/default.services.yml
    # This is not applicable when a queue is suspended but does not specify
    # how long to wait before attempting to resume.
    suspendMaximumWait: 30
+
+  # Development mode.
+  #
+  # Set to 'true' to enable more verbose error messages. We try to not only log
+  # errors, but also display them when in development mode. This is unrelated to
+  # development specific settings, such as disabled TWIG caching or aggregated
+  # CSS and JS.
--- a/core/modules/system/system.install
+++ b/core/modules/system/system.install
    }
  }

-  // Add warning when twig debug option is enabled.
+  // Add warnings for development mode.
-  // Add warnings for development mode.
+  // Add warning for development mode.
--- a/sites/default/default.services.yml
+++ b/sites/default/default.services.yml
    # This is not applicable when a queue is suspended but does not specify
    # how long to wait before attempting to resume.
    suspendMaximumWait: 30
+
+  # Development mode.
+  #
+  # Set to 'true' to enable more verbose error messages. We try to not only log
+  # errors, but also display them when in development mode. This is unrelated to
+  # development specific settings, such as disabled TWIG caching or aggregated
+  # CSS and JS.